UPDATED:

Can you offer me some information as I'm trying to put together data for the developers to see if we can find out what is going on.

Please tell me: What OS you use - Windows 10, 11, MAC, Linux ? What version of Thunderbird are you using?

This setting is commonly used: View > Folders > ALL But do you use any of the other views eg: Favourite, Unified, Unread, Recent ? Do you use those other views on a regular basis or sometimes? Which views do you use ?

For those folders with an incorrect 'drafts/letter' icon - have they been set up as a 'Favourite' ? Right click on folder with a 'drafts/letter' icon - is 'Favourite folder' selected ?

Please post an image showing the Folder Pane, so we can see the problem.

Do you experience a problem with any of the 'drafts/letter' icon folder emails ? eg: when you select an email so it displays in the Message Pane, does it look like a draft email, so buttons like 'Reply,forward etc' are missing ? OR are emails ok it is just the folder icon looking like a draft icon ?

Many thanks for helping.

I'm posting another comment with some instructions on attempt to fix.

In Thunderbird Menu app icon (3 lines) > Help > More Troubleshooting information Under 'Application Basics' - 'Profile Folder' - click on 'Open Folder'

A new window opens showing contents of your profile name folder.

Exit thunderbird now - this is important.

Scroll down, locate and delete the following files:

• folderTree.json
• global-messages-db.sqlite
• panacea.dat
• session.json
• virtualFolders.dat

Click on 'Mail' folder

• Delete this folder: 'smart mailboxes'

Start Thunderbird

Please report back on whether this sorted the problem.

Thanks OS - Windows 11 Thunderbird version 91.8.0 (32-bit) [Although my laptop is 64 bit] Setting selected: View > Folders > ALL Don’t use any of the other views - ever Folders with an incorrect 'drafts/letter' icon have NOT been set up as a 'Favourite' ? A right click on folder shows 'Favourite folder' is not selected Image showing the Folder Pane attached Note: the one with the blue line was created as a subfolder within the past month (and showed as such) but has changed to “letter” within the past week or so. The issue just started since the beginning of 2022.

Tried the deleting process but no change.

FYI - when I right click on the "letter" image, there is no option to delete like there is when a subfolder image is right clicked.

I am curious about whether others have experienced this.

Just to add...These subfolders are populated both by dragging items from the Inbox and by sending a copy using Write>Options>Send a copy to.

I believe the effected folders have got a folder flag for drafts.

Please use this addon:

• https://addons.thunderbird.net/en-us/thunderbird/addon/folderflags/

How to install addon:

• https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

If you download the xpi file - image below is a guide.

Once addon extension is installed and is visible in 'Menu app icon > Addons and Themes' > Extensions: Right click on effected folder and select 'Properties' Select the 'Flags' tab uncheck any flag that has been set, let me know what flags were set. click on OK

Thank you! That did the trick. Each was flagged as Draft. I unchecked it and the symbol changed to folder. I was able to delete the unwanted subfolder and rename the one I kept to the desired name.